Thanks to technological developments in microelectronics, it is now possible to integrate several complex functions on the same component to improve its performance. The integration of passive components and, more specifically, capacitors in integrated active or passive circuits is an important issue for developers. In fact, during the integration of such components, technological compatibility problems arise between the processes for manufacturing capacitors, for example, and passive or active components. In addition, storage requirement problems connected to the use of high-value capacitors arise.
Solutions have been explored, such as for example, the creation of Metal-Insulator-Metal (MIM) capacitors with anodizable layers enabling MIM deposition to be done inside holes obtained in said anodized layer.
Thus for example, a process enabling an MIM capacitor to be produced using an anodized layer is proposed in the NATURE TECHNOLOGY publication of May 2009, “Nanotubular metal-insulator-metal capacitor arrays for energy storage” by P. Banerjee et al. This publication presents a method of etching by anodizing an anodizable layer, enabling an MIM capacitor structure to be created. The MIM capacitors thus created enable capacitance values to be controlled in a relatively accurate way. However, such structures have relatively high internal resistance, which degrades the performance of such components and limits their integration in active circuits.
In addition, despite relatively high area ratios, thanks to the use of anodized layers, the densities of MIM capacitors thus obtained remain relatively low. Consequently, during the design of high-value capacitors, space requirement problems associated with this type of technology arise.